Question

Blood glucose levels for obese patients have a mean of 100 with a standard deviation of
15. A researcher thinks that a diet high in raw cornstarch will have a positive effect on
blood glucose levels. A sample of 36 patients who have tried the raw cornstarch diet
have a mean glucose level of 108. Test the hypothesis that the raw cornstarch had an
effect or not.

Answer 1

Ho : = 100
Ha : 100

Level of Significance (l.o.s.) : = 0.05 (assumed)

Decision Criteria : Reject Ho at 5% l.o.s. if Z cal > Z tab,
where Z tab = Z (/2) = Z (0.025) = 1.96

Calculations :   = 108, n = 36 and   = 15

Z cal = = = 3.2

Conclusion : Since Z cal > Z tab, we reject Ho at 5% l.o.s. and thus, conclude that the raw cornstarch had an
effect on the mean glucose level.

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